Structural ceramic materials generally show many advantages in high performance materials applications because of their high mechanical strengths and hardness properties and low weight. These features make many of these ceramic materials attractive for use in military applications such as armor for vehicles. Numerous non-military applications for these materials are just beginning to be explored and implemented.
Unfortunately, a major disadvantage of most structural ceramic materials is high cost. High cost limits the use of these materials both in military and non-military applications.
The high cost of many structural ceramics may be partly attributed to high cost of the starting ceramic powders which are to be shaped and densified to form structural ceramic parts. The starting powders are often made by energy-intensive processes or by other expensive methods adapted to produce high purity starting powders. Generally, it has been preferred to minimize the impurity contents of starting powders in order to maximize the performance of the ultimate ceramic part.
Some prior art processes have used chemical reactions in the formation of solid solutions containing AlN and SiC, however these processes generally use silicon carbide as a starting material and consequently still involve substantial starting material expense. U.S. Pat. Nos. 4,141,740 and 4,569,922 may be noted in this regard.
Needless to say, it would be highly desirable to reduce these costs associated with structural ceramics. Indeed, reduction of cost is necessary if structural ceramics are to be used in broader non-military applications.